Mr Ruddy is expected to join the families of the Disappeared for their annual wreath laying ceremony at Stormont in Belfast on Wednesday.

"As each year passes it gets harder to bear the pain but we will never lose hope and we pray that we will be able to lay Seamus to rest with our mother and father and now (brother) Sean.

"It is where he should be," he added.

For the last decade, relatives of the Disappeared have staged the walk on All Souls Day to highlight the cases of those still to be found.

They walk from Carson's Statue to the steps of Parliament Buildings where a black wreath, with attached white lilies representing those still missing, is laid.

Of the 17 Disappeared victims, some 13 have been recovered by the Independent Commission for the Location of Victims' Remains (ICLVR) - a body set up by the British and Irish governments during the peace process.

As well as Mr Ruddy, the remains of Columba McVeigh, cistercian monk Joe Lynskey and SAS-trained Captain Robert Nairac have not yet been located.

Last June Kevin McKee and Seamus Wright were found in a shallow grave in Coghalstown Co Meath.

An inquest into their deaths is due to be held in Dublin later this month.

Meanwhile, the sisters of Brian McKinney who vanished in 1978 will also take part in the walk.

His mother Margaret, now aged 84 and too frail to join the solemn procession, first raised the plight of the disappeared when she met US president Bill Clinton at the White House in 1998.

A transcript of a telephone conversation between Clinton and the then prime minister Tony Blair released earlier this year revealed the former president had been so moved by her story that he pushed for the Disappeared to be key focus for the peace process.

Mr McKinney's remains were found in Co Monaghan in 1999.

Sandra Peake from the Wave Trauma Centre, which supports the families, said: "It's impossible to over estimate the impact on the families of having their mother or father, brother or uncle taken from them in this way.

"If we have learned anything about dealing with the legacy of the past in Northern Ireland it is that time and mortality will not resolve it.

"Mothers who put their sons' names on the family headstone literally passed on the responsibility of bringing him back to the next generation.

"The families will continue to stand together until all the disappeared are brought home."

Geoff Knupfer, who leads the ICLVR investigations, will also take part in the event.

Anyone with information should contact the ICLVR's confidential telephone number on 00800 5558 5500 or write to them on ICLVR, PO BOX, 10827, Dublin 2.